This kind of positioning apparatus is described in Japanese Patent Public Disclosure No. 11-10468. The positioning apparatus in the prior art is composed as follows.
That is, a flange of a retracting nipple fixed to a movable member is fitted into a fitting straight hole opened in a support surface of a reference member, by which the axis of the straight hole is aligned with that of the retracting nipple, and then the movable member is positioned in the reference member by pulling the retracting nipple.
However, the prior art contains several problems. That is, in order to attach the movable member to the reference member smoothly, it is required to provide a diametrical fitting gap between the fitting straight hole and the flange. Consequently, the fitting gap reduces the positioning accuracy of the movable member against the reference member.
The present invention aims at smoothly attaching a movable member to a reference member and aligning these members accurately.